TY - JOUR A1 - von der Au, Marcus A1 - Borovinskaya, O. A1 - Flamigni, L. A1 - Kuhlmeier, K. A1 - Büchel, C. A1 - Meermann, Björn T1 - Single cell-inductively coupled plasma-time of flight-mass spectrometry approach for ecotoxicological testing N2 - Diatoms play a key role in assessing the eco-toxicology of metals and are already part of several national and international guidelines and regulations. Data on metal uptake and its correlation with a natural metal composition of the diatoms are mostly lacking on a cellular basis - mainly due to the lack of a suitable method on both the preparation and detection side. Therefore, within this work a fully automated approach based on the on-line coupling of a high performance liquid chromatograph (HPLC) and an inductively coupled plasma-time of flight-mass spectrometer (ICP-ToF-MS) was applied to analyze single cells of the alga Cyclotella meneghiniana multi-elementally in order to provide a deeper insight into the metal composition and its response to environmental stress. Multi-elemental analysis in single diatoms also enables assessment of combined toxicity of a set of metals. A set of four fingerprint elements, characteristically for diatoms (Mg, P, Si, Fe), were identified and hence the investigation of environmental stress onto the cells was enabled by performing incubation experiments with environmentally relevant toxic elements. It could be shown at moderate environmental stress caused by increasing the metal concentration in the medium (zinc) that the fingerprint element concentrations remained stable and thus the suitability of the selected elements for algae tracing was demonstrated. With regard to further ecotoxicological assessments, a multivariate approach was successfully applied allowing for cell classification upon different incubation concentration levels. This multivariate approach also facilitated an effective identification of three different diatom species (Cyclotella meneghiniana, Thalassiosira weissflogii and Thalassiosira pseudonana). KW - ICP-TOF-MS KW - Ecotoxicological Testing KW - Diatoms PY - 2020 DO - https://doi.org/10.1016/j.algal.2020.101964 VL - 49 SP - 101964 PB - Elsevier B.V. AN - OPUS4-50875 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - von der Au, Marcus A1 - Schwinn, M. A1 - Kuhlmeier, K. A1 - Büchel, C. A1 - Meermann, Björn T1 - Development of an automated on-line purification HPLC single cell-ICP-MS approach for fast diatom analysis N2 - The most challenging part in performing a single cell ICP-MS (sc-ICP-MS) approach is the sample preparation, in particular the reduction of the ionic background. This step is, in many cases, time-consuming and required for each sample separately. Furthermore, sc-ICP-MS measurements are mostly carried out "manually", given the fact that present systems are not allowing for an automated change of samples. Thus, within this work, we developed an approach based on a HPLC system coupled on-line with sc-ICP-MS via a set of switching valves as well as an in-line filter for automated cell washing. This set-up enables the ionic background removal as well as analysis of single cells completely automated without any manual sample pretreatment. Our approach was applied for the analysis of the single celled diatom species Cyclotella meneghiniana, a marine diatom species, on the basis of Mg24 and facilitates testing in 11 min per sample, requiring only around 10,000 cells in a volume of 10 µL and approx. 10 mL of a 5% MeOH/95% deionized water (v/v) mixture. Even at extremely saline culturing media concentrations (up to 1000 mg L-1 magnesium) our on-line approach worked sufficiently allowing for distinction of ionic and particulate fractions. Furthermore, a set of diatom samples was analyzed completely automated without the need for changing samples manually. So, utilizing this approach enables analyzing a high quantity of samples in a short time and therefore in future the investigation of ecotoxicological effects is simplified for example in terms of metal accumulation by taking biovariability into account. KW - Single cell-ICP-MS KW - Diatoms KW - Ecotoxicology testing KW - Automated system PY - 2019 DO - https://doi.org/10.1016/j.aca.2019.05.045 SN - 1873-4324 VL - 1077 SP - 87 EP - 94 PB - Elsevier AN - OPUS4-48567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -